Sound reproducer



Aug. 25, 1925. 1,551,105

l Y H. c. HAYES SOUND REPRODUCER Filed March 2, 1925 2 Sheets-Sheet l Aug. 25, 1925. A

H. c. HAYES 1551'105 SOUND REPRODUCER Filed March 2, 1925 2 Sheets-Sheet 2 Patented Aug. 25, 1925.

l UNITED STATES `HARVEY C. HAYES, 0F WASHINGTON, DISTRICT 0F COLUMBIA.

SOUND REPROD'UCER.

Application filed-laren 2, 1925. Serial No. 12,603. i

T0 all whom t may concern: p

Beit known that I, HARVEY C. HAYES, a citizen of the United States of America, and a resident 0f Washington, District of Columbia, have invented new and useful Improvements in a Sound Reproducer, of which the following is a specification. y

My invention relates broadly to sound reproducers and more particularly to sqund reproducers employing relatively large diaphragms for the amplification of soun The object of my invention 1s to provide means in a sound reproducer for compensating for variations in temperature and humidity conditions which normally cause warping and distortion of the sound reproducing diaphragm with such resulting displacement of theA operating parts as to impair the operation of the reproducer..

My invention finds particular application -`in electromagnetic sound reproducers of the conicaldiaphragm construction where the driver or electromagnetic devices impart vibrations to the cone by a link connection between a vibrating armature and the apex of the cone.

The apparatus described herein is particularly applicable to reproducers of radio concerts, news, lectures, music and other entertainment. The conical diaphragms are normally constructed of a material which is subject to change under variation of humidity and temperature resulting in the warping or change of sha in the diaphragm. Such change in s ape' often rel sults in shifting the position of the armature member to such an extent that l, it may be obstructed in movement by striking against the ole faces of the electromagnetic driver there y distorting or destroying the quality of the received sound. Conical diaphragm reproducers of large size offer so serious a problem by reason of changes in the shape of the cone caused by change of temperature and humidity, that heretofore they have required considerable readjusting from time to time to maintain the operating armature centrally between -the pole faces of the operating magnets. Suchv readjustments are undesirable as introducing complications not understood by` the average person and as requiring dependence upon the human equation for the maintenance of the reproducer after final factory inspection of the instrument.

The invention will be more clearly understood from the specification hereinafter following by reference to the accompanying drawings, wherein:

Figure 1 is a theoretical diagram explaining the principle of my invention; Fig. v2,

is a schematic arrangement describing the I' medium or when aviscous'iiiedmm is caused Y' Y, y,

toiw' racross a solidsurface.`

Referring to Figure 1 of the drawings,

assume a force F in a direction parallel to a small surface A which drags this surface through a viscous medium with velocity V in a plane parallel with large fixed plane CB. The istance between planes A and CB is represented as S. Therefore, the force F is directly proportional to the area A and the velocity V and to the coefficient of viscosity N of the medium F and inversely proportional toS in accordance with the following equation:

vAN.

From above it will be seen that avery slow motion V will require but 4a very small force F to produce such -motion whereas a rapid movement Vfwill require an enormous force F. i

In Figure 2 numeral 1 represents a rod terminated'by a cylinder 2 which contains a plunger 4 perforated by a hole 5 and connected to a' piston rod 3. The cylinder 2 is filled with a liquid having viscosity coefficient N. The piston can be moved out and in the cylinderby applying a push or pull force F on rod 3. A small force will produce' a slow but definite velocity of motion while great force will be required to produce aY rapid l motion of the piston through the cylinder. It will, therefore, be seen that a Acouplin is provided between members 1 and 3 w ereby a small steady force applied to one member will allow such member to move with respect to the other member but whereby the two members are almost rigidly connected so far as rapid motion of either member is concerned.

This kind of coupling proves valuable for linking certain types of electromagnetic drivers to sound reproducing or receiving diaphragms where the nature of the diaphragm is such that the line adjustment of the apparatus is impaired thro'ugh slow warping of the diaphragm caused by change of temperature or humidity. Such a case is represented in Fig. 3 wherein numeral 6 represents a magnetic armature of an electromagnetic device mounted so as to rotate about pivot 7 at 11 and linked with a conical diaphragm 8 by means of member 3. To function properly armature 6 must be held out and between the two pairs of magnetic poles 9 and 10, and to accomplish such adjustment the member 7 is secured to member 6 through a suitable torsion connection at 11. Vhen the magnets 9 and 10 cause the armature 6 to operate the torsion seated at 11 is twisted laterally through a short distance. rlhis torsion member serves to hold the armature 6 out and between the two pairs of magnets 9 and 10 but is not strong enough to hold the armature 6 in this position against the forces transmitted through link 3 caused by expansion or contraction of the paper cone under the action of a change of temperature or of humidity. However, if member 3 contains a viscosity coupling of the nature of that shown in Figs. 2 and 4: wherein the viscosity coupler 16 consists of a small tube 12 filled with a viscous substance 14 and into which a wire or link 3 extends, then the slow warping of the diaphragm will be taken care of by; a slight motion within the viscous coupler' 16 while the rapid vibrations imposed upon 3 by the vibratory armature 6 will be transferred across the viscous coupler 16 and the diaphragm 8, the same as if the coupling 16 were entirely rigid.

The dotted line showing in Figure 3 is intended to illustrate in exaggerated form the distortion or change in shape of the sound reproducing diaphragm 8 under conditions of humidity or temperature change.

The armature 6 has been shown moved over into dotted line position in such manner that it strikes against opposite pole pieces 9 and 10. Under these conditions the sound reproducing system instead of imparting a pleasing sound to the listener will merely reproduce a clatter by the armature 6 striking the pole pieces by reason of the fact that the diaphragm 8 has changed its shape. By my invention, I confine the movement of the armature 6 to a free space between the pole pieces, permitting the free vibration of the armature without chatter against the pole pieces independent of the change in shape of the diaphragm S. In other words, by employing the viscosity coupler of my invention I secure permanency of adjustment in the cone reproducer under all conditions, which has not been possible heretofore.

In Figure 5 I have illustrated more clearly one of the practical embodiments of the viscosity coupler 16. Only such str'ucture of the diaphragm and connecting link has been illustrated in order to clearly express the invention.

I have illustrated the principle of the invention in the several views heretofore described, but I desire it to be understood that various methods of carrying out the invention may be employed and that the particular structure shown is not to be considered in the limiting sense. I may vary the construction of the viscosity coupler and provide any element. between the driving mechanism and the sound reproducing dia phragm which will operate to readily conduct vibrations in the nature of sound vibrations encountered over the musical scale in the range of voice frequencies of a high order of magnitude per second while the coupler will change its 'characteristics under conditions of gradual change of temperature and humidity conditions. The viscosity coupler permits the change in characteristic of the coupling means between the driver and the diaphragm while the diaphragm retains substantially its original characteristics independent of change of temperature or humidity conditions.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States, is as follows:

1. A sound reproducer comprising in combination a sound reproducing diaphragm, means for imparting sound vibrations to said diaphragm and means interconnecting said aforementioned means and said diaphragm, said last mentioned means being arranged to change in characteristics under conditions of humidity and temperature change while said diaphragm retains substantially its original characteristics.

2. A sound reproducer comprising in combination a sound vibration device, a sound reproducing diaphragm and means connecting said sound reproducing device with said sound reproducing diaphragm comprising a coupling member, adapted to transfer vibrations of a high order of mag nitude from said sound reproducing device to said sound reproducing diaphragm while preventing the transfer of slow movement 'forces between said sound reproducing mechanism and said sound reproducing diaphragm.

3. A sound reproducer comprising in combination sound vibrating means, a dia- :fly

phragm for reproducing the sound vibrations and means interlinking said sound vibrating means and said diaphragm including a viscosity coupler having characteristics adapted to vary under temperature and humidity changes while said diaphragm retains .substantially its original characteristics.

4. A sound reproducing apparatus including in combination an electromagnetic sound vibrating means having an armature co-operating with a plurality of pole pieces, a sound reproducing diaphragm, a connection between said armature and said sound reproducing diaphragm and means interposed in said connection and maintaining said armature within a free vibrating space between said pole pieces independent of changes of temperature and humidity con-V ditions.

5. A sound reproducing apparatus comprising in combination a relatively large conical diaphragm, an electromagnetic operating mechanism including a plurality of pole members and an armature arranged to be vibrated between said pole members, a link connecting said armature with the apex of said conical diaphragm and means interposed in said link whereby the range of vibrations of said armature is confined to a free space between said pole members without striking said pole members independent of changes in shape of said conical diaphragm under conditions of temperature and humidity variations.

6. A sound reproducing apparatus com prising in combination a relatively large conical diaphragm, a driver for operating said diaphragm, said driver including an electromagnetic system and a movable armature co-operating therewith and means interposed between said movable armature and said conical diaphragm for maintaining said armature in spaced relation from said electromagnetic system independent of changes in shape of said diaphragm due to temperature and humidity variations.

7 A sound reproducing apparatus comprising a relatively large sound reproducing conical diaphragm, a driver for said diaphragm, a link connecting said driver and said diaphragm and a viscosity coupled disposed in said link and adapted to vary in length under conditions of temperature and humidity changes whereby change in shape of said diaghragm may be compensated by corlresponding changes in length of said lin r.

8. A sound reproducing apparatus comprising in combination a conical diaphragm, a driver for said diaphragm, a link connecting said driver with said diaphragm and means interposed in said link between said driver and said diaphragm, comprising a cylindrical member, a piston operating in said cylindrical member and viscous material in said cylindrical member against which said piston operates, said material having characteristics whereby said link may impart vibrations of high magnitude to said diaphragm without relative movement between said piston and said cylindrical member but arranged to move relatively with respect to each other under conditions of slow movement arising out of the gradual change in shape of said diaphragm under conditions of temperature and humidity variations.

HARVEY C. HAYES. 

